Question

Suatu fungsi f(X)=ax+b, jika f(1) = -4. f(3) = 2, maka nilai f(-5) adalaah

Answer 1

F(x) = ax + b
f(1) = a + b = -4 ----> a = -b - 4 (pers 1)
f(3) = 3a + b = 2 (pers 2)
Substitusi pers 1 ke pers 2
3a + b = 2
3 (-b - 4) + b = 2
-3b - 12 + b = 2
-3b + b = 2 + 12
-2b = 14
b = 14/-2
b = -7

a = -b -4
a = -(-7) - 4
a = 7 - 4
a = 3

maka nilai f(-5)
f(x) = ax + b
f(-5) = 3 (-5) + (-7)
f(-5) = -15 - 7
f(-5) = -22

Answer 2

F(x)=ax+b
f(-1)=-4
f(3)=2
maka f(-5)=?
-4=a+b
2=3a+b
________ -
-6=-2a
-6/-2=a
3=a

2=3a+b
2=3(3)+b
2=9+b
2-9=b
-7=b

f(-5)=ax+b
=3(-5)+(-7)
=-15-7
=-22

semoga membantu^^